oct- 15, 1946- . a ROSS ETAL 2,409,390 PROCESS FOR SIIULTAHEOUSLY ISOIERIZING AND SEPARATING CYCLOPARAFFIHS PRO‘ AGYCLIC PARAFFINS BY MEANS 4 OF AN ALUIIHUI HALIDE-HYDROCARBON COMPLEX Filed Dec. 4. 1944 V A Frac?omi fv T . 37 2 3 an“ is % ~lnvzn+brs= wiuims’ 5.2055 Philip Pezz-aq?a Patented Oct. 15, 1946 2,409,390 UNITED STATES PATENT OFFICE 2,409,390 PROCESS FOR SIMULTANEOUSLY ISOMER IZING AND SEPARATING CYCLOPARAF FINS FROM ACYCLIC PARAFFINS BY MEANS OF AN ALUMINUM HALIDE-HY DROCARBON COMPLEX William E. Ross, Berkeley, and Philip Pezzaglia, Oakland, Calif., assignors to Shell Development ‘ Company, San Francisco, Calif. Application December 4, 1944, Serial No. 566,538 10 Claims. (01. 260-666) 1 2 This invention relates to an improved process for the separation of cycloparaf?ns from hydro carbon mixtures comprising cyclopara?ins in ad the hydrocarbon, mixtures comprising open chain paraflins and cycloparai?ns of non-hydroaroé matic structure to isomerizing conditions eiiect ing'the conversion of non-hydroaromatic cyclo para?ins to hydroaromatic cycloparaf?ns and mixture with open chain paraf?ns. The inven tion relates more particularly to an improved thereafter subject the entire hydrocarbon mix ture to fractionation to separate fractions com prising desired cyclopara?ins. Although such a procedure enables the production on a practical scale of certainof the, naphthenic hydrocarbons such as, for example, cyclchexane in relatively process for the production of cyclo-paraf?ns of hydroaromatic structure from hydrocarbon mix tures comprising openschain paraf?ns and cyclo para?ins of non-hydroaromatic structure. The cycloparaiiins have become of exceeding ‘importance as starting materials and interme diates in the production of a wide variety of organic products. concentrated form it still does not enable the attainment of desirable yields in even such sped The most fertile source of ci?c instances. Thus, in the production of cyclo these highly desirable materials resides in the ‘hydrocarbon mixtures obtained in the natural 15 hexane from hydrocarbon mixtures such as naph thenic gasolines as resorted to heretofore, the state as petroleum, and in the products obtained gasoline is generally ?rst fractionated to sep in the thermal or catalytic treatment of petro arate a methylcyclopentane fraction, thus leav leum or distillate fractions thereof, and in the ing the greater portion of cyclohexane and also thermal or catalytic treatment such as, for ex ample, hydrogenation of carbonaceous materials, 20 a considerable amount of methylcyclopentane in a higher boiling fraction. Separation of such etc. As is well known, the cycloparaf?ns in these cyclohexane from the higher boiling hydrocarbon readily available hydrocarbon mixtures are found fraction by means such as simple distillation is therein in admixture with open chain para?ins. highly impractical due to the presence therein Realization of the full advantages inherent in the many chemical processes relying upon the‘ 25 of hydrocarbons such as, for example, dimethyl cyclopara?ins as starting or intermediate mate 'pentanes boiling in the same range as cyclo rials has heretofore been seriously handicapped hexane. subjection of the methylcyclopentane fraction to isomerizing conditions under the con by the lack of a process enabling the eflicient sep ditions resorted to heretofore generally does not aration on a practical scale of the cyclopara?'jns ‘from the open chain paraf?ns in admixture with 30 enable the attainment of a high conversion ap Which they are generally encountered. proaching equilibrium conversion of methylcyclo Thus, pentane to cyclohexane. Resort to the use of separation of the cyclcparaflins from open chain higher contact times though resulting in higher paraf?ns having the same, or approximately the conversion generally does not occasion a corre same number of carbon atoms to the molecule,v by such methods as fractional distillation if at 35 sponding increase in the quantity of cyclohexane recovered due to a greater increase in the rate all possible is often rendered so complex and of undesirable side reactions‘ resulting in the con delicate an operation as to render it highly im version of both methylcyclopentane and cyclo hexane to a higher boiling product.‘ After such practical. Of the cycloparaf?ns, those of hydroaromatic structure are of particular value and ?nd appli 40 an iso-merization operation the highly vexing problem of separating the naphthenic hydrocar cation in the production of an exceedingly wide bons from other hydrocarbons of close boiling range of valuable organic products. The pro duction of cycloparaf?ns of hydroaromatic struc range admixed therewith remains. Thus, sep aration from the cyclohexane produced of the ture in a state of required purity is rendered close boiling hydrocarbons such as dimethylpen even more di?icult since, to the difficulty of their ,tanes,‘ generally encountered therewith, by meth separation from open chain para?ins is added the often equally vexing problem of their sep aration from isomeric non-hydroaromatic cyclo para?ins and other hydrocarbons of close boil ing range or capable of forming azeotropes there with. By the term “hydroaromatic cycloparaf ?ns” as used throughout this speci?cation and appended claims is meant the cycloparamns hav ing a hexamethylene ring such as, for example, cyclohexane and the alkyl cyclohexanes, to dis tinguish them from cyclop-ara?ins of non-hydro aromatic structure comprising those having pentamethylene rings such as. for example, ods utilized heretofore is highly impractical. A further dif?culty inherent in these processes is due to the fact that in the isomerization of hy 50 drocarbon mixtures generally available compris ing both normal hexane and methylcyclopentane the proportion of methylcyclopentane initially present which is converted to cyclohexane ex ' ceeds the proportion of normal hexane converted ‘to isohexane, thereby resulting in a progressive increase of normal hexane concentration in the unconverted portion of the charge recycled to the reaction zone to further complicate the sep aration problems encountered. It is thus clearly methylcyclopentane and the alkyl cyclopentanes. It has been suggested heretofore to- subject (i0 .' apparent that the advantages inherent in such 2,409,390 3 4 processes as available heretofore in even such speci?c cases are limited. tion of cyclopara?ins and particularly the cyclo para?ins of hydroaromatic structure, these proc Separation of cycloparaf?ns having more than six carbon atoms to the molecule from the highly complex hydrocarbon mixtures in which they are esses also suffer from an inability to attain con encountered presents even greater difficulties. In these cases the problems encountered in attempt matic structure to cyclopara?ins of hydroaro version equal to or approximating equilibrium conversions of cycloparal?ns of non-hydroaro para?ins are in no Wise overcome by ?rst isomeriz matic structure when effecting the separation process under isomerizing conditions. Increasing the time of contact between solvent and hydro ing the hydrocarbon mixture as a whole under isomerizing conditions resorted to heretofore. Such methods do not provide a practical answer, for example, to the production of hydrocarbons carbons essential to the attainment of higher con version rates results, as shown above, in the loss of a substantial amount of cyclopara?ins due to the increase in reaction rates of side reactions ing to e?ect substantial separation of the cyclo predominating in methylcyclohexane from the converting cyclopara?‘lns to higher boiling mate readily available hydrocarbon mixtures compris 15 rials. ing the non-hydroaromatic cyclopara?ins having It has now been found that separation of seven carbon atoms to the molecule in admixture cyclopara?ins from para?inic hydrocarbons ad with open chain para?ins having seven and eight mixed therewith is effected with even greater e?iciency by distilling the cycloparaffin-contain atoms to the molecule and having the same boil ing range. 20 ing hydrocarbon mixture in the presence of a In its broadest aspect the object of the present countercurrent stream of preformed organo-metal invention is to provide an improved process en halide complex. By maintaining suitable isomer abling the more efficient separation of cyclo ization conditions in the extractive distillation para?ins from hydrocarbon mixtures comprising zone the cycloparaf?ns of non-hydroaromatic cycloparaf?ns and open chain paraf?ns. structure present in the hydrocarbon mixture A more particular object of the invention is the are converted to cycloparaf?ns of hydroaromatic provision of a process enabling the more efficient structure during the cyclopara?in separation. separation of cyclopara?ins from hydrocarbon Separation of the cycloparaf?ns from hydrocar mixtures comprising cycloparaf?ns and open bo-n mixtures comprising them by means of ex chain para?lns under isomerizing conditions. Another object of the invention is the provision of a process enabling the more ei?cient separation of cyclopara?ins from hydrocarbon fractions com prising cycloparaf?ns and open chain para?ins having substantially the same number of carbon atoms to the molecule. Another object of the invention is the provision 30 tractive distillation under hydrocarbon isomeriz ing conditions in accordance with the process of the invention enables the attainment of substan tially equilibrium conversions of cyclopara?ins of non-hydroaromatic structure to cycloparaf?ns of hydroaromatic structure in the absence of any substantial loss of cycloparaf?ns due to their con version to higher boiling products, thereby pro viding signal advantages over the liquid phase extraction method as well as over other processes separation of cyclopara?‘ins of non-hydroaromatic structure from hydrocarbon mixtures comprising 40 available heretofore for the production of cyclo para?ins of hydroaromatic structure. cycloparaf?ns and open chain para?ins with si In accordance with the process of the invention. multaneous conversion during the separation of the hydrocarbon charge comprising a mixture of non-hydroaromatic cycloparaf?ns to hydro aromatic cyclopara?ins. cyclopara?ins and open chain para?ins such as, of an improved process enabling the more e?icient A further object of the invention is the pro r for example, a naphthenic straight run gasoline vision of an improved process for the more e?l fraction optionally predominating in hydrocar cient production of hydrocarbons predominating bons having substantially the same number of carbon atoms to the molecule, such as a hexane or heptane fraction, is introduced into a distilla tion zone comprising, for example, a fractional distillation column. Into the upper part of the column there is introduced a preformed organo in cyclohexane from hydrocarbon fractions com prising open chain hexanes and methylcyclo pentane. Still another object of the invention is the pro vision of an improved process for the more e?i cient production of methylcyclohexane from hy drocarbon fractions comprising open chain paraf ?ns and cyclopara?ins of non-hydroaromatic structure having seven carbon atoms to the mole cule. Other objects and advantages of the in vention will become apparent from the following description thereof. It is known that unsaturated hydrocarbons, such as ole?ns and aromatic hydrocarbons, which react readily with aluminum chloride are removed from hydrocarbon mixtures containing them by treatment with aluminum chloride. In copending metal halide complex obtained by the interaction of a metal halide of the Friedel-Crafts type and i an organic compound, resulting in the contacting of the upwardly rising hydrocarbon vapors with a descending stream comprising hydrocarbon re flux and organo-metal halide complex. The ratio of the organo-metal halide solvent introduced into the column to the hydrocarbon charge is main tained suf?ciently high to assure a homogeneous liquid phase in equilibrium with the vapor. Con ditions within the column are controlled to result in the production of overhead vapors comprising application, Serial Number 538,192, ?led May 31, 1944, now Patent 2,382,445, of which the present application is a continuation-in-part, it has been shown that saturated hydrocarbons of cyclic ' paraf?nic hydrocarbons and a liquid bottom prod structure comprising the cycloparaf?ns can be zone wherein hydrocarbons comprising the cyclo uct comprising organo-metal halide complex and cycloparai?ns. Bottoms from the extractive dis» tillation zone are passed to a solvent separating separated efficiently by liquid phase extraction 70 para?ins are separated from the organo-metal under suitable conditions with a preformed com plex obtained by the interaction of a metal halide of the Friedel-Crafts type and an organic com pound. Though such liquid phase extraction re sults in substantial improvement in the produc halide solvent. The cycloparaf?ns eliminated from the complex separating zone are introduced into a product separating zone wherein separation of cyclopara?ins into fractions predominating in 7 cyclopara?'ins of particular composition is eifected, 2,409,890 6 ‘Within column. ‘Lthe hydrocarbon mixture charged thereto through line 6 is ‘subjected to frac tional distillationrwith the aid of suitable heating means comprising heater 9, closed heating coil 10 ‘and; controlledintroduction of re?ux into the The vapor overhead from‘ the extractive distil lation column, comprising the para?inic. ‘hydro carbons,-is passed through a condensing zone into an accumulating. zone. ‘A. portion :of the con densate is taken from the accumulating zone and passed as re?ux to the distillation zone. ‘ upper part of the column. ‘ ‘ . A preformed organo-metal halide complex is introduced into the top of fractionatingcolumn By maintaining suitable cyclopara?in isomeriz ing conditions within the extractive distillation zone, comprising the introduction of a hydrogen ‘I by means of valved line L2. The fluid organo vinto the extractive distillation zone, and the metal halide complex is prepared by‘ mixing a metal halide of the'Friedel-Crafts type, for‘exam maintenance'therein of ‘conditions de?ned more ple, a halide of aluminum such as aluminum chlo halide or a material‘ affording a hydrogen halide ride and/or aluminum bromide with an organic fully below, the isomeriz’ation of cyclopara?ins compound under suitable conditions resulting in such as, for example, the conversion of cycle parflins of non-hydroaromatic structure to cyclo~ 15 the interaction of the'metal halide with. theor ganic compound and/or decomposition-products para?ins of hydroaromatic structure is accom plished simultaneously with the extractive distil lation operation. ‘ When the extractive ‘distillation zone is thus maintained under cyclopara?ln isomerizing con thereof. Suitable organic compounds with which the metal halide may be combined under con ditions resulting in the obtaining of a desired 20 organo-metal halide complex comprising,‘ for ex ditions, vapor overhead eliminated therefrom and ample, aromatic hydrocarbons such as benzene, the hydrocarbons comprising cycloparaf?ns elimi nated from the organo-metal halide complex‘so-l matic kerosene extract; cyclic ole?ns such as toluene; hydrocarbon fractions such as an arc fractions comprising the hydrogen halide are cyclohexene, cyclopentene, and alkyl derivatives thereof; para?inic and ole?nic hydrocarbons of straight or branched chain structure; phenols; organic acids; ethers, etc. Of the suitable organo metal halide complexes, those comprising the ‘alu recycled to the extractive distillation zone. minum chloride-hydrocarbon complex are some vent separating zone are passed in separate streams to‘independent stripping zones wherein the hydrogen halide promoter admixed therewith is separated as gaseous fractions. The gaseous ’ In order to set forth more clearly the nature of 30 the invention it will be described herein in detail what preferred. ‘ l , The rate of introduction of the organo-metal halide complex into the column may vary consid with reference to the attached drawing in which erably within the scope of the invention. ‘The the single ?gure represents a more or less dia ratio of solvent introduced into the column to hy grammatic elevational view of one form of appa ratus suitable for executing the process of the 35 drocarbon is, however, maintained su?iciently high to maintain a homogeneous liquid phase in equilibrium with the vapors at all times. Rae A hydrocarbon mixture of relatively wide boiling tios of org‘ano-metal halide solvent to hydrocar range comprising cycloparaf?ns and open chain bon feed of from about 4:1 to about 30:1 have para?ins such as, for example, a naphthenicgaso line is forced by means of pump I through line 2 40 been found satisfactory. Higher or lower ratios of solvent to hydrocarbon may, however, be em into a feed fractionating zone. Suitable heating ployed within the scope of the invention. Par means such as, for example, a hydrocarbon ?uid af?nic hydrocarbon reflux is introduced into the heater or indirect heat‘ exchanger 3 is positioned in line 2. ‘The feedfractionating zone is depicted upper part of the column, preferably above the point of introduction of the organo-metal halide ‘in the drawing by a single fractionator 5 for the solvent by means of line l3. Conditions of tem purpose of simplicity. It will be understood that perature maintained within column 1' will, of in actual practice more than one such fractionat'dr course, vary in accordance with the nature of the may be employed toeffect the desired feed frac hydrocarbon mixture introduced therein. Condi tionation. Within ‘feed fractionator 5 there is separated a fraction of intermediate boiling tions within the column are, however, at all times carefully controlled to effect the separation of a range. The fraction of intermediate boiling range vapor fraction consisting predominantly of paraf may comprise, for example, hydrocarbons having ?nic hydrocarbons from a liquid fraction consist six atoms to the molecule, such as 'a hexane frac ing predominantly of organo-meta'l halide com ' tion comprising open chain hexanes, methylcyclo plex and cyclo-paraiiins. pentane and cyclohexane. Although a hexane Liquid bottoms comprising the organo-alumi fraction is chosen in the present illustrative de invention. ~ ' ‘ ' i ‘ ‘ num‘ chloride complex and cyclopara?ins are scription it is to be understood that the inven tion is in no Wise limited to the’ separation of a hexane fraction‘as a fraction of intermediate boil ing range. Thus, the intermediate boiling range fraction may comprise hydrocarbons having seven carbon atomsto the molecule; a hydrocarbon mix ture of wider boiling range comprising both valved line l5 and heat exchanging means l6 into a complex separating zone. The complex sepa rating zone may comprise a still l'l. "Within still ' Cs and C7 hydrocarbons, or a hydrocarbon mixture Vapors comprising methylcyclopenta'neiand cyclo comprising or predominating in‘ hydrocarbons hexane are passed from still ll through line" l8 and cooler l9 into an accumulator 20. The cyclo parar?ns maybe removed from accumulator 20 having more than ‘seven carbon atoms to the molecule. The hexane fraction is passed from fractionator -5 through line 6 into an extractive distillation The extractive distillation zone may com " zone. prise a fractionating column ‘I. A valved line passed from the lower part of column 1 through H the hydrocarbons comprising cycloparaf?ns are distilled from the organo-metal halide complex. through valved line ‘M as a ?nalproduct. A ‘part of the cyclopara?ins is, howeverepreferably passed through lines 23,, 24 and 25 into a fraction ator 26. Within fractionator 26 a vapor fraction comprising methylcyclopentane is separated from a liquid fraction comprising clycohexane. ,The 4 is provided for the introduction of hydrocarbon charge directly into line 6. The hydrocarbons so . liquid fraction is eliminated from fractionator 26 introduced by means of line 4, may constitute a part or all of the hydrocarbon charge to column ‘I. 75 through valved line 28 as a ?nal product. The 2,409,390 vapor-fraction is eliminated from fractionator 26 through valved line 29. , ' The vapor overhead from extractive distillation column 1 comprising open chain hexanes is passed through line 3| and cooler 32 into an accumulator 33. A portion of they para?lnic condensate is passed from accumulator 33 through lines 34 and B as re?ux into the upper part of fractionator 1. 8 Overhead comprising unconverted .methylcy clopentane, eliminated from column 26 through line 29, is recycled at least in part to extractive distillation column ‘I, by means of lines 43 and 6, .or is subjected to the extractive distillation in accordance with the invention in a separate ex tractive distillation zone not shown in the draw mg. - Although the separation of the organo-metal Separation of cycloparaf?ns from the metal halide solvent from cyclopara?ins is accomplished 10 halide hydrocarbon complex solvent, it has been by ‘distillation in the above illustrative description found, is facilitated by effecting such separation of the invention, other means of effecting such within still 1 in the presence of additionally in separation may be resorted to. ' The complex may troduced hydrogen halide. A valved line 45 is be separated from cycloparaf?ns by scrubbing the therefore provided to enable the passage of hy mixture with a suitable hydrocarbon such as, .for drogen chloridev from line 36 into line I5 carry example, a low boiling-saturated hydrocarbon, ing ‘liquid bottoms from extractive distillation suchzas butane or pentane; as disclosed in copend column 1 into still ll. In a further modi?cation ing-application, Serial No. 538,893, ?led June 6, of the invention hydrogen halide, for example, .1944, now Patent 2,382,445. hydrogen chloride, is introduced into still l'l A particular advantage of the invention resides "-20 through line 45, but no hydrogen halide is in in the ability to recover the naphthenic hydrocar troduced into extractive distillation column 1. bons of non-hydroaromatic structure, originally Column 1 will then function as described above present in the charge, in the form of naphthenic to effect the separation of cyclopara?ins from hydrocarbons of hydroaromatic structure. Thus, para?ins in the absence of any substantial cyclo in the treatment of a naphthenic hexane fraction paraf?n isomerization, whereas in still I‘! isom containing methylcyclopentane, maintenance of erization of cyolopara?ins, for example, con suitable .cycloparaf?n isomerizing conditions version of cyclopara?ins of non-hydroaromatic within column 1 enables the conversion of meth structure to cyclopara?ins of hydroaromatic ylcyclopentane to cyclohexane during the ex structure will take place. Under these condi tractive distillation operation. To attain these 30 tions still I’! will function as a cyclopara?in isom objectives a hydrogen halide promoter such as, for example, hydrogen chloride, or a material affording the hydrogen halide under the condi tions maintained in column 1, is introduced into the lower part of the column through valved line 35 at a point below the introduction of the charge. A part of the hydrogen chloride may be intro duced directly into line 8 from line 36. The hy— erizing zone. Organo-aluminum chloride complex, substan tially free of cycloparat?ns, is eliminated from still I‘! through valved line 46 and introduced into line l2, passing into the top of column ‘I. The temperature of the recycled complex is ad justed by suitable ‘means so that it is introduced into column 1 at a temperature substantially drogen chloride promoter is introduced at such a equal to the temperature in column 1 at the point rate as to maintain a concentration of- the hydro 40 of its introduction. gen halide in the column in the range 01? from Hydrocarbon mixtures comprising naphthenic about 0.1 to about 2.0 and preferably from about hydrocarbons often contain, in addition to open 0.1 to about 0.5 per cent by Weight of the hydro chain para?ins, a certain amount of aromatic carbon in the column. hydrocarbons. Thus, the naphthenic hexane When thus maintaining cyclopara?'in isomeriz 45 and/or heptane fractions will generally com ing conditions within column ‘I, the vapor over prise a certain amount of benzene and/or toluene. head passing from extractive distillation column This material may be removed from the charge ‘I through line 3| will contain hydrogen chloride. by suitable pretreatments prior to introduction The hydrocarbons comprising hydrogen chloride into column 1. The organo-aluminum chloride within accumulator 33-are forced through line complex, it has been found, however, is far more 31 into a stripping column 38. The hydrogen selective as a solvent for aromatic hydrocarbons chloride thus separated in column 38 is passed than for cyclopara?ins. Distillation within still therefrom through lines M, 36 and 35 into col I‘! of the liquid bottoms emanating from column umn ‘I. ‘Make-up hydrogen chloride is intro ‘I under conditions effecting the separation of duced into the system by means of valved line. ; cyclopara?ins from the complex will generally 42. Para?inic hydrocarbons comprising open result in a retention in the complex of at least chain hexanes are eliminated from the lower part a substantial amount of the aromatics originally of stripping column 38, through valved line 44, present in the charge. In a modi?cation of the as a ?nal product. invention, when the charge to the system com Bottoms from extractive distillation column ‘I prises aromatic hydrocarbons, at least a part of will generally be free of any substantial amount the complex eliminated from still I‘! is passed of hydrogen chloride. vWhen, however, hydrogen through line 48, containing heat exchanging chloride is present in the hydrocarbons in ac means 49, into a third distillation zone compris cumulator 20, because, for example, of separate ing, for example, still 50. Within still 50 the complex, substantially free of cycloparaflins but still containing aromatic hydrocarbons, which hydrogen chloride introduction into still H as described more fully below, the hydrocarbons con taining hydrogen chloride are passed from ac cumulator 20 through lines 23 and 39 into a separate stripping column 40. Overhead con in the treatment of naphthenic hexane fractions will comprise benzene, is subjected to more drastic distillation conditions to effect the separation of taining hydrogen chloride is recycled from strip substantially all of the benzene. The more ping column 40, through lines 36 and 35, to ex drastic conditions may be obtained by distilla tractive distillation column 1. Cyclopara?‘ms tion at a higher temperature by means of heat comprising cyclohexane and unconverted methyl input into heating means 49 and closed heating cyclopentane are passed from stripping column coil 5|, by prolonged residence time in still 50, ,40 through valved'line 25, into fractionator 26. 75. by use of subatmospheric pressure, by the in 2,409,390 10 troduction of stripping gases such as hydrogen, from methylcyclopentane and cyclohexane is‘ ef methane, ethane, nitrogen, etc., through valved fected in the process of the invention. In the distillation of a separate portion of the same full hexane fraction utilized as charge‘ in the above line 52, or hydrogen chloride through line 53, or by any two or more of these expedients. Vapors. comprising benzene are eliminated from still 50 example under substantially identical conditions but in the absence of the hydrocarbon-aluminum through valved line 54. Organo-aluminum chlo ride complex, now free of any substantial amount of benzene, is taken from still 50 through valved chloride complex solvent, it was found that all of the dimethylpentane content of the feed was contained in the bottoms of the distillation col line 55, and is recycled at least in part through lines 56, 46 and [2 into the upper part of frac tional distillation column ‘I. _ , umn. ' 1. The process for the separation of ‘cyclopar af?ns comprising methylcyclopentane from a hy drocarbon mixture containing said cyclopara?ins in admixture with open chain para?ins having substantially the same boiling range with simul taneous conversion of methylcyclopentane to oyclohexane during said separation which com prises subjecting said hydrocarbon mixture to The following examples are illustrative of the isomerization of cyclopara?ins with simultaneous separation of cycloparaihns from admixtures with open chain para?ins in accordance with the proc ess of the invention. Example ‘In a series of separate operations, ‘portions of a full range hexane fraction, obtained by frac fractional distillation in a fractionating zone, in Per cent by volume troducing a preformed aluminum chloride-hydro carbon complex into the upper part of the frac tionating zone, introducing hydrogen chloride into a lower part of the fractionating zone, there _________________ __ 33 a by simultaneously converting methylcyclopentane tional distillation of napthenic ‘ straight‘ run ~ gas oline, and having the following composition: Naphthenes: Methylcyclopentane '‘ We claim as our invention: ‘ Cyclohexane ________________________ __ 21 to cyclohexane and forming a vapor fraction pre dominating in para?ins and a liquid fraction pre Methylpentanes _____________________ __ dominating in aluminum chloride-hydrocarbon 1 Normal hexane ______________________ __ 34 complex and cycloparaf?ns comprising cyclohex Dimethylpentanes ________ __‘ ______ _i____ ane, separately removing said vapor and liquid fractions from the fractionating zone, and sep Benzene , 4 . 7 arating cycloparaf?ns comprising cyclohexane were subjected to extractive distillation under isomerizing conditions in a 40 bubble plate frac from said liquid fraction. , ‘ 2. The process for the separation of cyclopar tionating column. ‘Into the upper part of the _ af?ns comprising methylcyclopentane from a hy column there was introduced a preformed hydro drocarbon mixture containing said cyclopara?ins carbon-aluminum chloride complex prepared from in admixture with open chain para?‘ms having equal parts of aluminum chloride and a kerosene substantially the same boiling range with simul extract having a boiling range of from 150°C. to taneous conversion of methylcyclopentane‘ to 200° C. Hydrogen chloride Was‘introduced in con 40 cyclohexane during said separation which com tinuous stream into the lower part of the extrac prises subjecting said hydrocarbon mixture to tion distillation column. Bottoms ‘from the ex; fractional distillation in a fractionating zone, in tractive distillation‘ column were passed into a troducing a preformed aluminum halide-hydro stripping column wherein separation of extracted carbon complex into the upper part of the frac hydrocarbons from complex ‘was accomplished. tionating zone, introducing hydrogen halide into Complex taken'from the bottom of the stripping 45 a lower part of the fractionating zone, thereby column Was‘recycle‘d to the upper partvof the ex simultaneously converting methylcyclopentane to tra'ctive distillation column. The recycle stream temperature, was adjusted to that within the cyclohexane and forming a vapor fraction pre dominating in para?ins and a liquid fraction pre fractional distillation column at the point‘ of its dominating in aluminum halide-hydrocarbon introduction. Conditions of operation as well as 50 complex and cyclopara?ins comprising cyclohex results obtained'are indicated in the following table: ' ane, separately removing said vapor and liquid “ fractions from the fractionating zone and sep arating cyclopara?ins comprising cyclohexane Run No. 55 from said liquid fraction. it 3. The process for the separation of cyclopar af?ns comprising cyclopara?lns of non-hydro 1723 aromatic structure from a hydrocarbon mixture Extractive distillation column: _ _ containing said cyclopara?ins in admixture ‘with ‘ Plates above complex introduction _________ __ Plates above feed introduction _____________ __ 6 28 60 hydrocarbon feed ___________ .__.;_ _________ .. 5.9 Volume percent alClircomplex in column__-_ . 92 1 Re?ux ratio at st1l1head_ ___________________ __ - H01 introduced-weight percent of hydro carbon [eed ____ -_. ............. .r . -._ 0 5 HOw. Temperature of stripping column, ° 0 Results: ‘ . » l_ openchain para?ins having substantially the same boiling range with simultaneous conver sion of cyclopara?ins of non-hydroaromatic structure to cycloparaf?ns of hydroaromatic Volume ratio of AlOli-complex charged to A Volume percent of naphtlienes in stripper structure during said separation which comprises subjecting‘ said hydrocarbon mixture to a frac tional distillation in a fractionating zone, intro ducing a‘preformed aluminum halide-hydrocar bon complex into the upper part of the fraction Percent of dimethylpentanes in feed rejected ating zone,‘ introducing av hydrogen halide into overhead in extractive distillation column .45 70 a lower part of the fractionating zone, thereby Oyclohcxane to methylcyclopentane, ratio in extractive distillation column bottoms, converting cycloparai?ns of non-hydroaromatic 82 100 percent of equilibrium .................... _ structure to cyclopara?ins of hydroaromatic structurewhile forming a ‘vapor fraction predom inating inparaf?ns and a liquid fraction predom It is seen from the foregoing example that sub stantial separation of even dimethylpentanes 75 inating in aluminum halide-hydrocarbon com overhead?uzn'n: _____________________ __'_. Percent of paraiilns in feed rejected overhead i in extractive distillation column .......... __ 79 71 ‘ NaC)“Olaf» 2,409,390‘ 12 11 plex in admixture with cycloparaifms comprising cyclopara?ins of hydroaromatic structure, sep arately removing said vapor and liquid fractions carbon complex in admixture with cyclopara?ins containing cyclohexane, and separating cyclo paraf?ns comprising cyclohexane from said liquid from the fractionating zone, and separating cyclo parainns comprising cyclopara?‘ins of hydroaro matic structure from said liquid fraction. 4. The process for the separation of cyclo GI fraction. 7. The process for the production of cyclo'par a?ins of hydroaromatic structure from a hydro carbon mixture containing cycioparairins com para?ins comprising cyclopara?ins of non-hydro prising aromatic structure from a hydrocarbonv mixture structure and open chain para?ins having sub containing said cyclopara?ins in admixture with open chain para?ins having substantially the stantially the same boiling range which comprises subjecting said hydrocarbon mixture to fractional distillation in the presence of a preformed. alu minum halidenhydrocarbon complex and hydro same boiling range with simultaneous conversion of cyclopara?ins of non-hydroaromatic structure to cyclopara?ins of hydroaromatic structure dur ing said separation which comprises subjecting cyclopara?ins of non-hydroaromatic gen halide, thereby simultaneously converting cycloparaf?ns of non-hydroaromatic structure to cyclopara?ins of hydroaromatic structure and forming a vapor fraction comprising para?ins and a liquid fraction comprising aluminum halide-hydrocarbon complex and cyclopara?ins of said hydrocarbon mixture to a fractional distilla tion. in a fractionating zone, introducing a pre formed. aluminum halide-containing complex- in teraction, product obtained by the interaction of an aluminum halide with an organic compound 20 hydroaromatic structure, and separating cyclo into the upper part of the fractionating zone, in paraf?ns of hydroaromatic structure from said troducing a hydrogen halide into a lower part of liquid‘ fraction. the fractionating zone, thereby converting cyclo 8. The process for the production of cyclopar paramns of non-hydroaromatic structure to cy a?‘ins of hydroaromatic structure from a hydro cloparaf?ns of hydroaromatic structure while 25 carbon mixture containing cyclopara?in‘s com forming a Vapor fraction. predominating in- par a?ins and av liquid fraction predominating in prising cyclopara?ins of non-hydroaromatic structure and open chain para?ins having sub organo-aluminum halide complex in admixture stantially the same boiling range which comprises with cyclopara?ins comprising cyclopara?ins of subjecting said hydrocarbon mixture to fractional hydroaromatic structure, separately removing 30 distillation in the‘presence of a hydrogen halide said vapor, and liquid fractionsrfromthe fraction and‘ a preformed metal halide-containing com ating zone, and separating cyclopara?ins com plex interaction product obtained by the interac prising cyclopara?ins of hydroaromatic structure tion of a metal halide of the Friedel-Crafts type from, said liquid fraction. and an organic compound, thereby simultaneous _5. The process for the separation of cyclopar af?ns, comprising. cyclopara?ins of‘ non-hydro 35 ly converting cycloparaffins of nonehydroaro aromatic structure from a hydrocarbon mixture matic structure to cycloparaf?ns of hydroaro matic structure and. forming‘a vapor fraction containing said cyclopara?ins in: admixture with open chain para?ins having substantially the comprising paraf?ns and a liquid fraction com prising said metal halide-containing complex and same boiling range with simultaneous conversion 40 cycloparaf?ns of hydroaromatic. structure, and of cyclopara?ins‘ of non~hydroaromatic structure separating cyclopara?ins of hydroaromatic struc to cyclopara?ins of. hydroaromaticstructure dur ture from said liquid fraction. ing said separation which comprises subjecting 9. The process for separating cycloparai?ns said hydrocarbon mixture toa fractionaldistilla comprising cycloparai?ns of non-hydroaromatic‘ tion in. a fractionating zone, introducing a pre 45 structure from a hydrocarbon mixture containing formed metal halideecontaining complex inter said cycloparaf?ns in admixture with open chain action. product obtained by. the interaction of a paraf?ns having substantially the ‘same boiling metal halide of the FriedelrCrafts type and an range with simultaneous conversion of‘ cyjclopar organic compound into the upper part of- the a?ins of non-hydroaromatic structure to cyclo fractionating zone, introducing a hydrogen halide 50 para?ins of hydroaromatic structure which ‘com into a lower part of the fractionatingzone, there prises subjecting said hydrocarbonv mixture to by converting cycloparaf?ns of non-hydroaro fractional distillation in a fractional distillation matic structure to cyclopara?ins of‘ hydroaro zone, introducing a preformed metal halide-con matic structure while forming a, vapor fraction taining complex interaction product obtained by predominating in para?finsand a liquid fraction 55 the interaction of a metal halide of the Friedel predominating in said metal halide-containing Crafts type and an organic compound into the complex in admixture with cycloparamns com upper part of the fractional distillation zone, in prising cycloparai?ns of hydroaromatic struc troducing a hydrogen halide intoa lower part of ture, separately removing said-vapor and. liquid the fractional distillation zone, thereby simul fractions from the fractionating. zone, and sep 60 taneously converting cycloparaf?ns of non-hy arating cycloparaf?ns comprising cycloparaf?ns droaromatic structure to cyclopara?ins of hydro of hydroaromatic structure from: said liquid aromatic structure and forming a vapor fraction fraction. predominating in paraf?ns in admixture with hy 6. The process for the production, of cyclo hexane from a hydrocarbon mixture containing 65 drogen halide and a liquid fraction predominat cycloparai?ns comprising methylcyclopentane and open chain paraf?ns having substantially the ing in said metal halide-containing complex in‘ admixture with cycloparaf?ns comprising cyclo para?ins of hydroaromatic structure, separately removing said vapor and liquidvfractions from the tion in the presence of a preformed aluminum 70 fractionating zone, separating" cyclopara?ins chloride-hydrocarbon complex and hydrogen comprising cyclopara?ins or hydroaromatic chloride, thereby simultaneously converting structure from said liquid fraction, passing‘ said methylcyclopentane to cyclohexane and forming vapor fraction from said fractionating zone to _ same boiling range which comprisessubjecting said hydrocarbon mixture to fractional distilla a vapor fraction comprising para?ins and a liquid a stripping zone, separating a; gaseous fraction fraction comprising aluminum chloride-hydro+ 75 comprising‘ hydrogen ‘halide inv said’v stripping 2,409,390 14 zone, and passing said gaseous fraction from said stripping zone to the fractionating zone. 10. The process for the separation of cyclo para?‘ins from a hydrocarbon mixture compris by the interaction of a metal halide of the Fried el-Crafts type and an organic compound, thereby isomerizing said cyclopara?in to a cyclopara?in of different molecular structure having the same number of carbon atoms to the molecule and con ing an isomerizable cycloparamn having at ‘least taining at least ?ve carbon atoms in the ring six carbon atoms to the molecule and containing while simultaneously forming a vapor fraction at least ?ve carbon atoms in the ring in admix comprising para?ins and a liquid fraction com ture with open chain paraf?ns having substan prising said metal halide-containing complex in tially the same boiling range while simultane ously isomerizing said cyclopara?in, which com 10 admixture with said isomerized cyclopara?in, and prises subjecting said hydrocarbon mixture to extractive distillation in the presence of a hy drogen halide and a preformed metal halide containing complex interaction product obtained separating cycloparaf?ns comprising said isomer ized cycloparaf?n from said liquid fraction. WILLIAM ‘E. ROSS. PHILIP PEZZAGLIA.